Difference between 3D solid types?

In my attached AutoCAD2010 .dwg...

Why are the white and green solids recognized as different types of solids? They look the same but AutoCAD doesn't recognize them as the same type of object. What all makes them different and how do you create one or the other?

To be more specific, with respect to grip enabled deformations for example…

For the rectangular solids, selecting the large white one [#2] gives grips for changing its size. But this doesn't happen on the small green one [#1], and ctrl-clicking it doesn’t make grips appear either. Nor does ctrl-clicking do anything different on the small green one compared to the large white one.

For the cylindrical solids,the same seems to be true for simple left-mouse-click selection (though the grip for increasing outside diameter doesn’t seem to work on the large white cylinder ). With respect to control-clicking though, control-clicking the small cylinder [A] reveals lots of grips, yet this doesn’t happen on the large cylinder.

It doesn't surprise me that boxes behave differently than cylinders, but even two cylinders can have different behaviors for some reason. Though my guess is it has something to do with one being recognized as a proper solid primitive and the other being just a generic solid with the same shape as a primitive, I don't understand the difference for sure.

solid differences.dwg

There is no difference in the "type" of solids in your file.

They are all 3DSOLID type.

If you do a LIst on the parts you will see some were created with History (solidhist) None and others with Record.

Was this a test question?

There is no difference in the "type" of solids in your file.

They are all 3DSOLID type.

 

If you do a LIst on the parts you will see some were created with History (solidhist) None and others with Record.

 

Was this a test question?

Well, if "type" isn't the right wording, we can use any word that's better, but that's not what my question is about. I'm just interested in why "Why are the white and green solids recognized as different"? ...as evidenced by all the examples I gave.

I can tell right away that solid history isn't the explanation because both rectangular solids have the same solid history (history=none) and both cylinders have the same history (history=record). So it stands to reason that you can't explain the difference between cylinder A & B with a solid history setting that is the same for both.

Primitives act differently than certain extruded profiles.

Primitives act differently than certain extruded profiles.

I wanted to keep my initial post short so I didn't add this...

Notice that in the CUI, for Quick Properties, underneath 3D Solids there is a big list of 3D primitives, then at the very end there is a solid "type (or whatever word you want to use)" called "None". In my attached drawing, the small green solids are both in that "None" category, yet the larger solids are in a specific primitive category, namely "Box" and "Cylinder".

So yeah, some are primitives. Some aren't, which is good to have confirmed. Can anyone give a lesson on the differences? Positives/negatives?, how is one created compared to the other?, and other questions I'm not even thinking of that are good to know?

The heart of the issue is that I find myself in the middle of a drawing and realize that a 3D solid isn't behaving as I'd expect, and often I'd imagine it's because it somehow became a non-primitive, yet I never explicitly tried to make it a non-primitive, nor do I thoroughly understand what makes them different, other than some of the observations I posted above.

Primitives:

http://exchange.autodesk.com/autocad/enu/online-help/search#WS1a9193826455f5ffa23ce210c4a30acaf-68d0.htm

Soon as solid models get manipulated you'll lose the functionality of the standard shapes (such as the grips). There are more tools to utilize, though. These grips are never truly "gone" if you look into sub-object selection modes. Here: http://exchange.autodesk.com/autocad/enu/online-help/search#WS1a9193826455f5ffa23ce210c4a30acaf-6784.htm

If you want to work with solid models that always maintain a higher level of parametric abilities, then look into moving on from AutoCAD, such as Inventor or Revit - depending on your background.

How they were made and edited determines how many editing grips they have. Extrude gives you the most, PP with selection inside the boundary is second, PP with boundary selection gives the fewest.

This is why I use extrude rather than PP depending on what I am working on.

Primitives:

http://exchange.autodesk.com/autocad/enu/online-help/search#WS1a9193826455f5ffa23ce210c4a30acaf-68d0.htm

 

Soon as solid models get manipulated you'll lose the functionality of the standard shapes (such as the grips). There are more tools to utilize, though. These grips are never truly "gone" if you look into sub-object selection modes. Here: http://exchange.autodesk.com/autocad/enu/online-help/search#WS1a9193826455f5ffa23ce210c4a30acaf-6784.htm

 

If you want to work with solid models that always maintain a higher level of parametric abilities, then look into moving on from AutoCAD, such as Inventor or Revit - depending on your background.

 

Thanks. And it looks like the only way to create a primitive is through the commands in the "Primitive" panel...all solids created in any other way will be non-primitive. I've got more for you though.

Obviously grip editing a primitive won't make it non-primitive. But is that really the only way you can edit a primitive safely? Presspull, extrude, union, subtract, fillet edge, etc. ...all typed commands that deform a primitive in some way will convert the solid to non-primitive?

I see you're a Revit user. But if you were to use AutoCAD on one of your projects, would you go to any effort to try to maintain a solid's primitive status, or would you just not worry about it because there are enough other ways to deform even non-primitives easily? Can solid history help a lot?

EDIT: rkent, I typed this before your post, but I'm reading it now.

My personal preference is to turn solidhist off, I have seen problems where the entire model is corrupted (in earlier releases, not sure about later releases).

I edit models with Ctrl select of faces or with the solidedit tools, occasionally grip editing.

I never use the primatives (for some reason I have always used extrude or press/pull even to create primitives like cylinders or boxes).

If you want true history based editing look into one of the modern CAD tools as suggested.

I edit models with Ctrl select of faces or with the solidedit tools, occasionally grip editing.

I never use the primatives (for some reason I have always used extrude or press/pull even to create primitives like cylinders or boxes).

I'll keep all that in mind. And rkent, your first post was exactly what I was looking to know.

I created a bunch of boxes and cylinders using different methods and saved it as a drawing that I'm attaching, if anyone is interested in comparing the grips for each one at a glance. I still think it's a little goofy that cylinder B has an arrow grip that doesn't seem to do anything, but that's not very important.

One more question...you know when you ctrl-select a face, edge, vertex, etc. and a little red dot appears that allows you to deform the solid? What is that type of deformation called? I can't look up more info on doing it that way (using a search engine) because there's no typed command for it and I don't know what to call it.

solid differences experiment.dwg

subobject selection

subobject selection

Thanks. I'd run across that term before (StykFacE mentioned it in this thread actually), but I didn't think it was the term I was looking for since I don't want to only select, I also want to deform. But I guess they go hand-in-hand together.

So if you've got a non-primitive solid face and you want to press-pull it out, but you could also sub-object select "move face", which way would you tend to choose to do it? And do you do it that way every time?

Marvin, please don't take offense to this statement but you're thinking way to far into the "primitive and non-primitive" concept. I know it can be hard to distinguish non-offensive posts on forums so I just wanted to be clear you understand where I'm coming from.

Sure, primitives have their very slight advantage in having a few extra native grips. This doesn't change the fact that you still have just as much control in manipulating solid models when they're not a primitive. Furthermore, the second you start manipulating basic primitive geometry, these little differentiation's go away immediately. This is probably why most of us don't even consider primitive solids because beyond a box, sphere, cylinder, etc... primitives are no more. Usually when you're wanting to model something in 3D, you're needing to go beyond a primitive anyways. Refer to my guitar modeling project in my signature to understand the detail level one can get in AutoCAD, which is the furthest thing from primitives.

Hope this helps.

Thanks. I'd run across that term before (StykFacE mentioned it in this thread actually), but I didn't think it was the term I was looking for since I don't want to only select, I also want to deform. But I guess they go hand-in-hand together.

 

So if you've got a non-primitive solid face and you want to press-pull it out, but you could also sub-object select "move face", which way would you tend to choose to do it? And do you do it that way every time?

I use Solidedit, Face, Extrude (which I have set to EED), then I have options for using a Path, and for tapering.

Sometimes PP makes sense and I use that but normally I like the other way.

I rarely use the sub-object method, but any of them work to get the job done.

Lots of ways to get stuff done, no one way is the right way.

I use Solidedit, Face, Extrude (which I have set to EED), then I have options for using a Path, and for tapering.

 

Sometimes PP makes sense and I use that but normally I like the other way.

 

I rarely use the sub-object method, but any of them work to get the job done.

 

Lots of ways to get stuff done, no one way is the right way.

Thanks. That's the perspective I was looking for. I figured there's no definitive answer for what is always better, I just wanted to make sure that there wasn't some rule of thumb that more experienced users are well-aware of. ...and I forgot about that solidedit extrude way of doing it, which is a third way on top of the two I mentioned.

Hey StykFacE, no offense taken. In fact, the reason why my last question specifically excluded primitives was because I had already decided (after reading all the page 1 posts and doing my little experiment) that going forward, I would worry less about losing the solid primitive grips.